Two-dimensional electron gas related emissions in ZnMgO/ZnO heterostructures

Abstract

Radiative recombination of two-dimensional electron gas (2DEG), induced by polarization and validated by Hall effect measurements, is investigated in ZnMgO/ZnO heterostructures grown by metal-organic chemical vapor deposition. The Mg composition, the depth profile distribution of Mg, the residual strain in ZnMgO caplayer, and the thickness of caplayer all significantly influence the 2DEG-related transitions in ZnMgO/ZnO heterostructures. Below or above ZnO donor bound exciton, three additional broad emissions persisting up to 100 K are assigned to the spatially indirect transitions from 2DEG electrons to the photoexcited holes towards the ZnO flat-band region or remaining at the heterointerface. V

Polarization discontinuity induced two-dimensional electron gas at ZnO/Zn(Mg)O interfaces: A first-principles study

“…23 Recently, a different type of system supporting a 2DEG, wurtzite ZnO/Zn(Mg)O heterostructures, has been investigated experimentally. [24][25][26][27][28][29][30][31][32] These heterostructures are usually grown using molecular beam epitaxy; 24,25 however, a 2DEG was also demonstrated in samples grown with metal-organic vapor deposition which is suitable for mass production. 30,31 The presence of the 2DEG is normally confirmed by Hall effect and capacitance measurements.…”

“…[24][25][26][27][28][29][30][31][32] These heterostructures are usually grown using molecular beam epitaxy; 24,25 however, a 2DEG was also demonstrated in samples grown with metal-organic vapor deposition which is suitable for mass production. 30,31 The presence of the 2DEG is normally confirmed by Hall effect and capacitance measurements. 24,27,28 The observation of the quantum Hall effect 25 and the fractional quantum Hall effect 29 in these heterostructures testifies to the high quality of these interfaces.…”

Luminescence from two-dimensional electron gases in InAlN/GaN heterostructures with different In content

“…17 and 18) and in ZnMgO/ZnO HS (Ref. 19) that were assigned to the recombination of electrons in the 2DEG and free holes in the buffer layer.…”

Properties of shallow donors in ZnMgO epilayers grown by metal organic chemical vapor deposition

“…The growth of the latter heterostructures by means of MBE and MOCVD has been reported. [1][2][3][4][5][6][7][8][9][10]20 The fabrication of p-type ZnO has also been reported by employment of different growth techniques. However, the realization of light emitting diodes (LEDs) has only been demonstrated for epilayer materials grown by MBE, 21,22 MOCVD, 23 and hybrid beam deposition.…”

“…The major research efforts have been focused on investigations and fabrication of ZnO related nanostructures, the p-type doping, and optoelectronic devices based on ZnO. The ZnO epilayers and nanostructures have been grown on various types of substrates by different techniques, such as molecular beam epitaxy (MBE), 1-4 metal-organic vapor phase epitaxy or metal organic chemical vapor deposition (MOCVD), [5][6][7][8][9][10] pulsed laser deposition (PLD), 11,12 the vapour-liquid-solid (VLS) catalytic growth technique, [13][14][15] magnetron sputtering, 16,17 and low temperature chemical solutions. 18,19 There are also great efforts to grow p-type layers of ZnO and ZnO based heterostructures (such as ZnMgO/ZnO, ZnBeO/ZnO, and ZnMnO/ZnO).…”